In spite of the great strides that have been made in various areas of clinical neuroscience, relatively little exploration has been performed to determine if such findings are ethnically consistent. What little data which do exist suggest that drastic ethnic differences in responses to biological treatment (such as psychopharmacology) and in psychobiologic processes associated with psychiatric disorders do occur. These findings have important clinical implications, particularly in relation to appropriate treatment and assessment of severely ill ethnic minority psychiatric patients. Furthermore, they also have important basic science ramifications, in regard to the universality of "psychobiological markers" and their pathophysiologic interpretations. In order to better understand the relevance of these scant but interesting and potentially important observations, the nature and extent of cross-ethnic dissimilarities will be ascertained, and the mechanisms underlying such differences will be assessed. To do so, we propose to establish a new multi-ethnic Minority Mental Health Research Center whose goals are to systematically study these vital and essentially unexplored areas. This Center will be multi- disciplinary in nature, will include researchers in diverse areas, such as psychiatry, minority research, biological psychiatry, and pharmacology. Three Core Facilities will be established. These will include the Administrative Core (with a statistical component), the Assessment and Subject Recruitment Core, and the Laboratory Core. Three pilot projects will be performed during this granting period. These projects will explore the following issues: (1) Ethnicity and differential responses to tricyclic antidepressants (Blacks, Hispanics, and Caucasians); (2) Ethnicity, lithium pharmacokinetics, and the RBC/plasma lithium ratio (Blacks and Caucasians), and (3) Ethnicity and biological markers in depression (Blacks, Hispanics and Caucasians). Besides providing valuable information that may be clinically relevant, these pilot projects will also provide data that will further guide our future research efforts in this area. The Center's Laboratory, although of modest size in the beginning, will be the National first Laboratory that will be primarily devoted to cross-ethnic research. The sharing of the Laboratory and other resources of this Center with other researchers, and collaboration with other researchers and institutions will be promoted.